The present invention relates generally to articles made of polymeric monofilaments, and more particularly, to looped bristles, methods for making looped bristles and bristle sub-assemblies, and monofilament bristle sub-assemblies connected to brush bodies.
The aforementioned co-pending application describes a manufacturing technique in which a base string is fed axially along a mandrel while at the same time a monofilament is wrapped around the mandrel, thereby producing a plurality of "wraps" which are transported along the mandrel by the base string. The wraps are then bonded to the base string using an ultrasonic welder, and subsequently cut to thereby form an article having two rows of monofilament segments connected to the base string.
This article, called a "bristle string," can then be cut to lengths and used to make a variety of brushes or other products requiring bristles. In one example, several rows of bristles are formed in a toothbrush by mounting the bristle string segments in the head portion of a toothbrush. Typically, the proximal ends of the bristles are connected to the brush head and the distal ends extend freely upwardly.
Brushes with looped bristles have been used in the past. For example, U.S. Pat. No. 4,211,217 to Gueret describes a hair and massage brush in which the bristles are bent to form loops which are anchored in perforations formed in the brush head fusing the ends together. As another example, U.S. Pat. No. 4,406,032 to Diamant describes a toothbrush which includes a filament wrapped around the head to form a plurality of circular loops.
U.S. Pat. No. 4,493,125 to Collis describes a toothbrush having a combination of curved bristles and straight bristles. The curved bristles were formed by having opposite ends of straight filaments embedded in the head of the toothbrush in groups, thereby forming loops. The loops are then cut axially to form two rows of curved bristles. Other examples where looped bristles are used in a toothbrush are shown in U.S. Pat. Nos. 4,030,845 to Deckert, 2,599,191 to Meunier, and 4,438,541 to Jacob et al.
While these show various forms of loop bristles, a need exists for a looped bristle structure that is relatively easy to manufacture and cost effective to produce.